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Unforced Variations: May 2013

Filed under: — group @ 3 May 2013

This month’s open thread.


551 Responses to “Unforced Variations: May 2013”

  1. 151

    who’s to say that the development of the first simplest self-replicating simplest organism didn’t take 100 million years or less. What basis do we have for assuming otherwise? After all Stanley Miller who stimulated much of the field of modern abiogenesis considered that the evolution of the first cyanobacteria might have taken 20 million years.

    I also think you need to loosen up your definition of ‘organism’ as well. Early forms were likely to have been transient chemical automata that only very loosely qualify as organisms. Cyanobacteria are fantastically complex and only arose after much early evolutionary selection occurred. Automata aren’t that hard to construct, I myself have a sequential 8 kilobyte 16 bit FORTH nucleus that can self recompile itself almost instantly, and with an additional 8 kilobytes of code turns into an operating system complete with editor, compiler, assembler and external interfaces. This is something I did very early on in order to simulate the biological process.

  2. 152
    Ray Ladbury says:

    Simon Abingdon,
    And yet, we exist. Funny, that.

  3. 153
  4. 154
    simon abingdon says:

    Imagine drawing the tree of life since abiogenesis (or biogenesis according to taste). Trace the incredibly, astonishingly lengthy path towards the emergence of homo sapiens (our only competitor in the intelligent ET race). Won’t the relentless succession of favourable branches in such an improbably successful evolution quite easily dwarf the number of stars within whose spheres other such lengthy (and possibly ET) evolutions might optimistically be taking place? And doesn’t the unexpectedness of homochirality compel a conviction of the uniqueness (at least here) of the original biogenetic event?

  5. 155
    Mal Adapted says:

    Claims that abiogenesis could not have occurred on the early Earth in the time before complex life appeared are, as was said in the previous thread, arguments from incredulity. It’s been pointed out that, without knowing the mechanisms of the individual steps, their likelihood can’t be estimated. That’s clear from a couple of articles in the current Nature Chemistry focus on prebiotic chemistry (h/t Pete Dunkelberg), demonstrating that a previous theoretical constraint on RNA auto-catalysis was too strict. In general, for a lower bound on likelihood, it’s not necessary to show that a step did occur by a particular mechanism, only that plausible mechanisms exist.

    “Evolution” is often said not to have begun until abiogenesis was complete, but what should we call the processes that created the environment in which abiogenesis took place? Between the Big Bang and the present, the primordial atoms of hydrogen and helium (plus a little lithium) were fused into new elements, which reacted in giant clouds to form molecules, which were gathered into planets, where they went on to form minerals and organic monomers. At every step, less stable configurations competed for constituents with more stable ones. I have no problem saying the Universe has evolved.

    For a highly-readable account of chemical, mineral and geologic evolution on the early Earth, whereby the stage was set for abiogenesis, I enthusiastically recommend The Story of Earth, by the geochemist Robert Hazen. Great stuff!

  6. 156

    #154–

    “Won’t the relentless succession of favourable branches in such an improbably successful evolution quite easily dwarf the number of stars within whose spheres other such lengthy (and possibly ET) evolutions might optimistically be taking place?”

    No, since unfavorable ‘branches’ also existed, and were selected against.

    “And doesn’t the unexpectedness of homochirality compel a conviction of the uniqueness (at least here) of the original biogenetic event?”

    No, since we don’t understand its emergence, even to whether or not it is related directly to ‘the original biogenetic event.’

  7. 157
    Hank Roberts says:

    Nuke the origins talk, I say …

  8. 158
    Ray Ladbury says:

    Simon,
    You are making assumptions with no data to inhibit your creativity–this is sometimes referred to pulling it out of your tuckus. You are assuming all the branch points are uncorrelated, even that left-handedness poses no evolutionary advantage (which it might have in some environments).

    Indeed, even your assumption of uniqueness in the origin of life is unwarranted–what we see is what survived and outcompeted everything else–that doesn’t mean it’s all there ever was.

  9. 159

    Impacts of declining spring snow cover in the Northern Hemisphere:

    http://www.sciencedaily.com/releases/2013/05/130507134421.htm

    “As is true for ecosystem changes anywhere, a decaying subnivium [sub-snow environment] would have far-reaching consequences. Reptiles and amphibians, which can survive being frozen solid, are put at risk when temperatures fluctuate, bringing them prematurely out of their winter torpor only to be lashed by late spring storms or big drops in temperature. Insects also undergo phases of freeze tolerance and the migrating birds that depend on invertebrates as a food staple may find the cupboard bare when the protective snow cover goes missing.”

  10. 160
    sidd says:

    Mernild et al. in Cryosphere discuss

    http://www.the-cryosphere-discuss.net/7/1987/2013/tcd-7-1987-2013.html

    with a nice calculation of future mass waste in glaciers and icecaps (does not include Greenland or Antarctica). The calculation is based on ratios of the area in accumulation to the total area of the glacier, regressed against mass balance to give the equilibrium (for a particular climate), which is then used in projecting future mass waste.

    “These losses imply global mean sea-level rise of 163 ± 73 mm, assuming total glacier volume of 430 mm sea-level equivalent.”

    In the body, they mention decade to century time scales.

    sidd

  11. 161
    David B. Benson says:

    simon abingdon @150 — Well done.

  12. 162
    sidd says:

    Mr. McKinney: Thanks for bringing that to my attention.

    Purely for anecdotal value, these coincide with my own observations.

    1)less snow in March-April. Check
    2)”spring melt has accelerated by almost two weeks” Check
    3)”plants exposed directly to cold temperatures and more frequent freeze-thaw cycles can suffer tissue damage both below and above ground, resulting in higher plant mortality, delayed flowering and reduced biomass” Check
    4)Fewer voles and shrews. Check
    5)”The effects will be especially profound along the trailing edge of the cryosphere in regions that experience significant, but seasonal snow cover”
    That last would be me.

  13. 163
    Edward Greisch says:

    What do you think of http://www.scirp.org/journal/PaperDownload.aspx?paperID=3217
    Vol.2, No.11, 1211-1224 (2010) Natural Science doi:10.4236/ns.2010.211149
    “On the recovery from the Little Ice Age” by Syun-Ichi Akasofu
    International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, USA; sakasofu@iarc.uaf.edu ?

    [Response: It's meaningless, like most (all?) papers that claim there is a "recovery" from the Little Ice Age. What is the mechanism proposed? Nothing but speculation plus a steadfast refusal to consider known forcings (i.e. greenhouse gases). --eric]

  14. 164
    sidd says:

    Akasofu(2010) does not convince me with (postulated) linear recovery from a (non global) LIA with a 60 yr oscillation, an obligatory nod to Scafeta misanalysis of solar influence, and a regular round trip of all the denialist references.

    Gone emeritus.

    sidd

  15. 165
    Martin Vermeer says:

    Simon Abingdon #150

    more than 80 potentially negative bifurcations

    With that logic, you couldn’t even travel from London to Paris — imagine all the potentially negative bifurcations along the way!

    Come to think of it, don’t get out of bed in the morning ;-)

  16. 166
  17. 167
    Rafael Molina Navas, Madrid says:

    #163 – Aparte from Erics´response, please note mean global temperatures are now even higher than in the Medieval Warm Period, a maximum previous to LIA minima …

  18. 168
    simon abingdon says:

    #158 Ray Ladbury “Simon, You are making assumptions with no data …”

    But at #36 you said “I agree that there is no evidence either way”.

    And at #152 “And yet, we exist. Funny, that”. Funny-peculiar indeed it is.

  19. 169

    #163 et seq.–Sounds like vintage Akasofu. I’ve encountered him before when cited by denialist commenters. Gavin’s question “What is the mechanism proposed?” cuts to the chase, from what I’ve seen previously–”recovery” is treated as if it were a mechanism.

    But climate isn’t a spring to be stretched (pun semi-intentional.)

    #162–Sidd, you are welcome. I used to live in such a zone myself.

    I was especially struck by that story, having earlier read Tamino’s analysis of the declining snow cover. The trends are very, very marked indeed, especially for spring and (though not so material to the present study) summer. It sounds as though there could be pretty serious disruption of ecosystems as transitions happen.

    (Though for the Meadow Vole–one of the more widely-distributed mammals of North America–I’m guessing the challenge is probably basically transitory. Certainly there is no shortage of them where I live now, in the American Southeast.)

  20. 170
    simon abingdon says:

    #165 Martin Vermeer “80 potentially negative bifurcations.. With that logic, you couldn’t even travel from London to Paris”.

    To get your train from London to Paris you’d need all 80 sets of points to be set correctly. If each was set randomly and independently Paris wouldn’t be your hoped-for destination unless you’d survived (correctly followed) each of 80 successive sets of points (bifurcations). I make the odds in favour of that to be 1 in 2^80. You have a problem with that logic?

  21. 171
    Guest says:

    #150, #154 and 161,

    Well done … NOT. First of all there were many aborted attempts to produce a hominid well before Homo sapiens sapiens came along. If it wouldn’t have been us it would have just been someone else. Secondly, as I have pointed out nucleosynthesis (yes, that is evolution too) did most of the heavy lifting well before the atoms met the proverbial primordial soup. One could even call the solar nebula the ‘primordial soup’. Quark soup anyone? What is only remarkable is the long term stability of the soups which produced the slimes. Yes, life is fortuitous, but this is a fortuitous universe, one in which life is demonstrated to exist at many many levels. Our lives just take more time then the other lives, but this is a universe where time, space and atoms are abundant, so the burden of demonstration is upon you, not on those who suggest life is abundant in this universe, because that has already pretty much been well established.

  22. 172
    jgnfld says:

    @169
    _But climate isn’t a spring to be stretched (pun semi-intentional.)_

    Quite. But weather is pretty much by definition such a spring as heat, moisture, etc. are pushed and pulled about. Hence the mechanism that allows the denialist FUD

    As for the negative effects on shrews and voles, I live in Newfoundland which has always had a very long freeze-thaw spring season which is very hard on many non-native plants and animals. For example, the bark on my tea roses is routinely lifted right off the stem by said cycle requiring extensive pruning as I do not otherwise protect them.

    But that said, there are plenty of shrews (introduced) and voles (native)…and VERY many insects for the shrews to feed upon (though not a great diversity of them ) which have successfully adapted. So at least some subspecies appear to be able to handle this sort of weather treatment.

    Expect diversity decreases, but there are plants and animals adapted to such conditions.

  23. 173

    And, in a more-or-less related development, 12 Canadian scientists “call out” Environment Minister Joe Oliver:

    http://www.cbc.ca/news/technology/story/2013/05/08/pol-climate-scientist-letter-joe-oliver.html

  24. 174

    Eric, sorry to misattribute your response to Gavin! (Inline, in response to Ed Greisch.)

    I need to work on care in reading, evidently.

  25. 175

    #165–Exactly.

    I recall writing a computer program to generate non-tonal ‘chorales’ for ear-training purposes, back in the ’70s–non-tonal chorales not being exactly thick on the ground in the real musical world. Apart from a user spec routine, the process started with the random number generator and then proceeded through a whole bunch of ‘negative bifurcations.’

    And yet, a suitable chorale emerged as output *every single time.*

    “[Negative] bifurcations”–AKA, the magic of selection.

  26. 176
    Hank Roberts says:

    > expect diversity decreases

    We’re not just losing a few individual species with lots left over.

    Less diversity, more damage to crops.

    http://onlinelibrary.wiley.com/doi/10.1111/ele.12096/full

  27. 177
    Hank Roberts says:

    DOI: 10.1111/ele.12096
    The loss of indirect interactions leads to cascading extinctions of carnivores
    Ecology Letters
    Volume 16, Issue 5, pages 664–669, May 2013

  28. 178
    Ric Merritt says:

    John Mashey, 166, notes the Amazon reviews of Dr Akasofu’s book.

    The ever-helpful Amazon list of “Customers who bought this item also bought” books is also amusing. You’ve heard of books that come wrapped in brown paper (obsolete now I suppose). The books on this list come wrapped in tinfoil, which can be reused for hats.

  29. 179
    Richard Hendricks says:

    My personal view is that life is very common in the universe, with complex life much less so, and advanced life even less, possibly less than one per galaxy.

    Given we only have a sample size of one, life seems fairly easy to start on a planet – pre-life complex molecules are reasonably abundant, and over a few million years would end up saturating any primeval ocean – no bacteria or oxygen to speed breakdown. And remember, those first billion or so years of Earth’s history are pretty violent, with asteroid impacts and probably much greater volcanic activity. How many times did primitive life get completely wiped out and have to start over from scratch?

    Complex life took much longer to evolve, so it’s natural to assume it is difficult. I also think the moon-creating event is critical to our current existence, because without it we probably would have a very thick crust like Venus, which would lead to hundreds of millions of years of no volcanic activity and then a near-complete overturning of the crust. My guess is this would lead to a large water-covered worlds due to erosion grinding them flat, with a smaller percentage of worlds with highly active volcanoes creating short-lived islands. This would force many resets in the evolution of life. Also, lunar tides were likely key in the colonization of land by forcing shore-living plants and animals to evolve to tolerate times out of the water. I am unsure of the effects of the lunar impact on atmosphere and climate, but I suspect it had a significant one, perhaps stopping a Venus timeline for Earth.

    Advanced life, say at our level, requires many coincidences to occur that limit it happening or time it exists. Where would humanity be without fossil fuels, for example? Could we have advanced past the iron age without coal or oil? What if a planet did not even have anything resembling woody plants – it would be hard to advance past a stone age in that case. If they have fossil fuels, how many discover nuclear power and manage to survive its discovery? Or survive the side effects of their own industrialization?

  30. 180
    simon abingdon says:

    #165 Martin Vermeer

    Martin, thank you for taking the trouble to comment on my #150. I’m glad my infelicitous phrase “negative bifurcation” was able to afford you some amusement but I’m sure you knew that I intended it to mean something like “a crucial point selecting for lack of survival fitness” or some such.

    So, while my original response to you languishes in moderation, may I offer a slightly more colourful scenario which perhaps more vividly demonstrates the point I was trying to make?

    Suppose your railway route from London to Paris encounters 80 sets of points along the way and suppose also that there is a sudden totally unanticipated fault in the system (a voltage spike perhaps) which causes each of the point settings en route independently to unlock then lock again in an unspecified direction, the controlling signal boxes meanwhile being unaware of the unfolding of these events.

    What do you think the chances of your train getting all the way to Paris in such circumstances might be? (Hint: it would be like tossing 80 heads in a row).

  31. 181
    JCH says:

    Links to some person’s paper (who has now gone to the great beyond, RIP) that “curve fits” an exponential to ~50 years of CO2 observational data using a baseline of 280 ppmv (which is valid for all time from the Big Bang to Infinity and Beyond or so JCH would appear to assume).

    I said depending on human behavior, which is a far cry from Big Bang to Infinity and Beyond. Each year the earth’s population has to get very busy to hit 2.67 ppm. It’s a huge effort, and they seem intent on building upon it each year for as long as they can.

    Why you feel the need to trash David Hofmann is interesting. The paper was co-authored by two notable scientists. One, Pieter Tans, is a co-author on the paper to which you linked. I think he’s fairly well versed on carbon dioxide.

  32. 182
    Hank Roberts says:

    > The ever-helpful Amazon list of “Customers who bought this item
    > also bought” books is also amusing.

    Wow. That’s a list that just goes on, and on, and on.

    “Casey’s research into the Sun’s activity, which began four years ago, resulted in discovery of a solar cycle that is now reversing from its global warming phase to that of dangerous global cooling for the next thirty years or more ….” — see http://issuepedia.org/Space_and_Science_Research_Center

  33. 183

    Advanced life, say at our level, requires many coincidences to occur that limit it happening or time it exists.

    Universes may require many coincidences as well to exist, whether they contain life capable of recognizing the breadths and depths their environment, or not. The question remains, do universes without life exist if they are not observed?

  34. 184
    Chris Colose says:

    In my last comment I’ve purposely avoided the topic of abiogenesis because I think it’s off-topic here, even for an open forum, but also because the conversation hasn’t been going anywhere substantive.

    Regardless, it’s quite clear that life got going on Earth within a billion years or so, and probably didn’t require anything absurdly unique to happen in order to do so. What’s more, most stars (e.g., smaller M-type stars) have even longer on the main-sequence than our sun, since the lifetime of hydrogen burning in the core is inversely related to the mass of the star. That gives planets orbiting those stars substantially longer to get things going.

    I’m far from up-to-date on the current literature regarding abiogenesis controversies and hypotheses, but I don’t gather that there’s any serious concern in the astrobiology community that getting life going is a once-in-a-universe event that poses a fundamental limitation for even discussing the issue. I tend to trust that if the problem were so hopeless, the current community would be more aware of this. All that said, I don’t have much problem accepting at face value that very simple life can originate fairly easily.

    A last word about “life” — astrobiologists are interested in any form of life, not just complex or intelligent life. For exoplanetary systems, the implicit assumption is usually that such life will interact sufficiently with the atmosphere in order to be detectable spectrally. In our own solar system, we might get to the point of finding subsurface life eventually, if it’s there. Finally, evolution does not proceed toward “homo-based species” or even toward “intelligence.” Humans are not some final step in the tree of life, as much as some people would like to think so. This really makes comments such as simon’s #154 irrelevant. No one is expecting to find something like “humans” elsewhere. The particular path that evolution took, and the eventual branch that led “us” is indeed unique, given that it’s an integrated function of environmental history and competition amongst species. That is not relevant for finding life elsewhere.

    The current paradigm of habitable limitations in the literature generally starts with the need for liquid water. This is primarily a climate question. Life exists on Earth basically everywhere that liquid water is present, even in some of the most extreme environments. Some people have speculated that even this liquid water criteria is unnecessary, potentially broadening the scope of what we consider to be habitable, but I think it’s a good starting point. There might be other issues, like the development of plate tectonics on “super Earth” sized planets.

    These criteria and most of the other things people are talking about are rather broad. The current models of the liquid water habitable zone are sufficiently wide. Thus, I think the real issue from here is technological rather than scientific.

  35. 185
    SecularAnimist says:

    Richard Hendricks wrote: “Could we have advanced past the iron age without coal or oil?”

    Steel manufacturing far precedes the use of fossil fuels.

    A high-grade form of carbon steel called “Wootz steel” was manufactured in India and Sri Lanka as early as 300 BCE. And high-carbon steel was manufactured in Sri Lanka using wind power as early as the 7th century CE.

    Ancient Smelter Used Wind To Make High-Grade Steel
    By John Noble Wilford
    The New York Times
    February 06, 1996

  36. 186
    Ray Ladbury says:

    Simon, You are assuming that viable genetic codes constitute disjoint points in the phase space of all possible combinations. It doesn’t work that way.

    Biology–yer doing it worng.

  37. 187
    David B. Benson says:

    Dust in the Clouds: Cirrus Clouds Form Around Mineral Dust and Metallic Particles
    http://www.sciencedaily.com/releases/2013/05/130509142104.htm
    No micro-organisms, no black carbon.

  38. 188
    David B. Benson says:

    Moon and Earth Have Common Water Source
    http://www.sciencedaily.com/releases/2013/05/130509142054.htm
    which is not comets, it seems. Raises many question of Terra/Luna formation anew.

  39. 189
    Phil Scadden says:

    simon – if you mean to imply the chance of something exactly like humans evolving elsewhere in the universe, then I agree the chance is vanishingly low. However, who says that life has to be like on earth, or that intelligence can only be like human? Evolution on earth has seen an increase in intelligence on many different lines of development. It seems a reasonable to expect that if humans vanished tomorrow, then eventually higher intelligence will appear from some other line. Maybe higher intelligence would happened much earlier if we didnt have KT extinction event.
    Personally, I find it more reasonable to expect that once life gets started, then higher intelligence becomes probable, given enough time.

  40. 190
    Jim Callahan says:

    Do alternating Arctic and Antarctic melts (opposite seasons in northern and southern hemisphere) cause semi-annual tidal peaks in equatorial regions? Would this be helpful in modeling sea level rise?

  41. 191
    Hank Roberts says:

    In case anyone wondered how it’s done these days:
    http://www.sfsignal.com/archives/2013/05/guest-post-guy-hasson-says-keep-it-stupid-simpleton/#more-75965

    —-snippet follows—–

    “… I got the sense I was going to experience something new. As an SF author, I couldn’t pass that up.

    “How can you help?” I said, sounding interested in whatever product she was shelling.

    “My name is Mary Belle, from Digital Kingmakers.”

    That’s a blunt company name. Do they really think people will fall for that promise?

    “…We’ll optimize the way you talk to your readers in various blogs. We know your audience. We can make you go viral.”

    My brain was going ding-ding-ding. One year ago, this was science fiction. Some people who’ve never heard of this may think it still is.

    She’d walked me through her company: three teams clicking away at social websites I’ve never heard of, two graphic teams hammering at creating marketing material for Digital Kingmakers, and one team of analysts and data miners.

    We sat in the conference room and she began her PowerPoint presentation. Its subject: GPO – Guest Post Optimization.
    —- end snippet—–

  42. 192
    D. Brookman says:

    @163, Note also that publication in a SCIRP journal is not a good sign.

  43. 193
    AIC says:

    Comment on paper released online May 9 in Science by Brigham-Grette et al on core analysis from Lake El’gygytgyn ?

    At approx 400ppm CO2, 8C warmer in summer about 3.6 – 3.4 million years ago.

  44. 194
    simon abingdon says:

    If tossing 80 heads in a row is more likely than the evolution of thinking then there are not enough stars for it to happen. The weak anthropic principle explains our overwhelmingly improbable existence.

  45. 195
    Chuck Hughes says:

    “It may seem impossible to imagine that a technologically advanced society could choose, in essence, to destroy itself, but that is what we are now in the process of doing.” So ends Field Notes from a Catastrophe, the terrific 2006 book by Elizabeth Kolbert, one of the country’s most thoughtful climate journalists.”

    http://thinkprogress.org/climate/2013/05/05/1940521/into-the-valley-of-death-rode-the-600-into-the-valley-of-400-ppm-road-the-7-billion/

    So I must ask…. is this hyperbole or accurate? I keep hearing these dire assessments and have to wonder, not being a scientist, IS this hyperbole?

    The article goes on to say:

    “Certainly as we hit 400 parts per million (ppm) for the first time in human existence, with not even a plan to avoid 600 ppm, 800 ppm, and then 1000 — not even a national discussion or an outcry by the so-called intelligentsia – it is worth asking, why? Is there something inherent in homo “sapiens” that makes us oblivious to the obvious?” ~ Joe Romm

    Thoughts? Observations? Perspective? Anyone?

  46. 196

    #185–Yes, from what I’ve read, charcoal was a very common fuel in early steel-making. As I recall, Diamond’s “Collapse” discusses this in the Norse context. Of course, it gets problematic if you want to make steel on an industrial scale, as the “Collapse” context also suggests–deforestation can easily result, and then you are once again degrading your local climate and ecology.

    In fact, IIRC, Diamond suggests that that dynamic may well have played out in Greenland–there are strong archaeological indications of both wood- and steel-poverty in the later Norse Greenlandic settlements.

  47. 197
    Radge Havers says:

    @~194

    “…oblivious to the obvious?”

    Well there are structural issues, but underlying those it always seems to come back to a mixture of tribalism and buggy wetware.

    It’s hard to come to terms with, but history is in some respects the story of collapsing societies. Now we’re global. If we go down, that’s the whole magilla.

    So here it is, on the one hand, climate scientists have raised warnings, in various styles, and can more or less back them up with the best reason we can muster. On the other hand, you have the claims of deniers, which a little skilled and honest diligence reveals to be largely irrelevant.

    So after a little thought, it can be seen to come down to a matter of degree. How bad is it going to get? Well that depends on what we do or don’t do. It’s pretty clear that we have the capacity to create hell on earth. Should we be concerned about that? It’s only a question because, as your queries demonstrate, this is a hard thing for humans to wrap their heads around.

  48. 198
    SecularAnimist says:

    Thomas Lee Elifritz wrote: “The question remains, do universes without life exist if they are not observed?”

    That is of course not a scientific question, since it cannot in principle be answered by empirical observation.

    “No phenomenon is a real phenomenon until it is an observed phenomenon.” — Niels Bohr.

  49. 199
    SecularAnimist says:

    Phil Scadden wrote: “However, who says that … intelligence can only be like human?”

    A suprising number of people, including some scientists, seem to have a problem recognizing the intelligence of non-human animals right here on Earth.

    Indeed, there is a sort of “denialism” about the sentience and cognitive capabilities of non-human animals that’s similar in some respects to global warming denialism.

  50. 200

    #194–Chuck, in my opinion it is not hyperbole at all. We can’t limit the range of risks well, which means that there is, as far as we can tell, a real risk of social collapse at various spacial scales as a result of climate change. There may even be a real risk of species extinction, though most here would probably assess that as relatively unlikely. (A very sizable global population crash might be another story, though.)

    As to the question, ‘is this a tendency in H. Sap?’ many here have referenced Jared Diamond’s book “Collapse” (as I did in my comment @ #195), which does such a good job of dissecting past societal collapses and their relation to ecological degradation. Clearly, it’s often the case that we humans often struggle to create sustainable ways of life–though Diamond also identifies success stories, such as (IIRC) the intensive agriculture practiced over very long timescales in the Papua New Guinea highlands.


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